Radio telephone in which an off operation of an operator-activated power switch is inhibited during a talk mode

ABSTRACT

A radio telephone apparatus, such as a car telephone, and the method of controlling a radio telephone apparatus, in which the OFF operation of a power source switch caused by an erroneous operation is inhibited when the radio telephone is in a talk mode. In more detail, the ON or OFF state of the power source switch is detected as well as whether or not the apparatus is in the talk mode, so that the switching of a power source line switch to its OFF state by means of the power source switch is inhibited in the talk mode and allowed only in a non-talk mode. Further, an ON/OFF function of a power supply of the apparatus as well as, for example, a muting function which is necessary only in the talk mode and which acts to attenuate a transmission talk voice, are allocated to one of keys in a dial key pad. The ON or OFF state of the allocated function key is detected to perform muting control based on the ON or OFF output of the function key in the talk mode and to perform ON/OFF control of the apparatus power supply in the non-talk mode.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to radio telephone apparatuses such as cartelephones and methods of controlling them and, more particularly, to aradio telephone apparatus and the method of controlling it wherein theoperation in which a power source switch is turned OFF by an erroneousoperation in a talk mode is inhibited.

2. Description of the Related Art

A prior art radio telephone apparatus, for example, a car telephonecomprises a transceiver unit and a control unit. The transceiver unitincludes a power supply circuit for receiving power from a battery togenerate necessary power source voltages, a controller, a radio circuit,an audio circuit, and a power source line switch provided between thebattery and the power source part. The control unit includes a key padthrough which a dial number or the like is input, a controller, ahandset receiver, a handset transmitter, a loudspeaker for generation ofa ringing tone, and a power source key input detecting circuit. Thecontrol unit is coupled to a party telephone set (an ordinary hometelephone set or another car telephone) through an antenna, a radiocircuit and a base station to form a talk path between the control unitand the party telephone set, so that a speech can be realized throughthe handset receiver and transmitter.

With the above arrangement, the power source switch for turning ON thepower supply of the apparatus is separately provided from the key pad,but recently the power source switch is often arranged to be one key ofthe key pad. In the latter case, a certain key of the key pad is used asthe power source switch so that continuous depression of this key for apredetermined period of time causes the power source key input detectingcircuit to detect the depressed state of the key, whereby the powersource line switch in the transceiver unit is turned ON. A secondcontinuous depression of the key for the predetermined period of timecauses the power source key input detecting circuit to detect the seconddepressed state of the key, whereby the power source line switch isturned OFF. In other words, each time the key, to which the power sourceswitch function is allocated, is continuously depressed (turned ON) forthe predetermined time, the power source line switch is alternatelychanged over from its ON state to its OFF state and vice versa.

Meanwhile, since the control unit is arranged to have the handsetintegrally built therein, the user must talk with the party holding thecontrol unit in his or her hand in a talk mode. For this reason, theprior art apparatus has a problem in that it is possible for the user toerroneously touch the key allocated as the power source switch duringthe conversation with the other party, which undesirably results in theapparatus power supply being turned OFF and thus the speech path wouldbe cut off.

Like the power source switch, a mute switch for interrupting atransmission voice at the call sender side to prevent the party fromlistening to the voice in the talk mode, a volume switch and other suchswitches are embodied respectively in the form of one key of the keypad.

In this way, in the case where keys of the key pad are arranged to beused as the power source switch, as the mute switch and as the volumeswitch, the controller in the transceiver unit periodically examines theON or OFF state of each of the keys of the key pad and compares orcollates the examined state with the previous ON or OFF state todetermine which key has been operated. For example, if one of the keyshaving a mute function allocated thereto is operated, then thecontroller which controls the transmission talk muting switch is placedin its OFF state, thus cutting or deadening a transmission talk voice.

Meanwhile, it is common that about 6-9 function keys including the muteswitch key are provided in a car telephone. With such an arrangement onefunction is allocated to one of the function keys of the key pad asmentioned above. However, when it is necessary to increase the number offunction keys for the system to accommodate more functions, the physicalsize of the key pad must be disadvantageously restricted, as well as thenumber of allowable additional function keys, thus resulting in a systemthat cannot cope with the increase in the number of function keys. Oneof the measures taken to solve this problem is to enlarge the size ofthe key pad. However, this measure disadvantageously involves theincreased size of the control unit containing the key pad.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a radio telephoneapparatus which can prevent the unintentional turning ON of a powersupply part and thus the cutting off of a speech path.

Another object of the present invention is to provide a radio telephoneapparatus which can satisfy a demand of increasing the number offunctions in the apparatus, while not increasing the number of keys in akey pad and also while not enlarging the size of the key pad.

The present invention is arranged to detect the ON or OFF state of apower source switch, detect whether or not the apparatus is in a talkmode, inhibit the switching of a power source line switch to its OFFstate by means of the power source switch in the talk mode and allow theswitching of the power source line switch only to the OFF state.

That is, even when the power source switch instructs the turning OFF ofthe power source line switch, this instruction will be invalidated andthe power source line switch will not be turned OFF so long as theapparatus is in the talk mode. And when an instruction of turning OFFthe power source line switch is issued from the power source switch in anon-talk mode, the power source line switch will be turned OFF.

The present invention is also characterized in that an ON/OFF functionof an apparatus power supply as well as a function only necessary in thetalk mode such as a mute function for attenuating a transmission talkvoice are allocated to one of the keys in a dial key pad. The ON or OFFstate of the above key is detected whether or not the apparatus is inthe talk mode through a spatial radio circuit, so that an ON or OFFoutput of the above key causes the mute control to be carried out in thetalk mode or causes the ON/OFF control of the apparatus power supply tobe carried out in the non-talk mode.

When the apparatus is in the talk mode, the ON or OFF output of one ofthe keys in the key pad having both the ON/OFF function of the apparatuspower supply and the mute function of attenuating a transmission talkvoice, is used to perform the mute control in the talk mode, while toperform the ON/OFF control of the apparatus power supply in the non-talkmode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an embodiment of the presentinvention;

FIG. 2 is a flowchart showing the power source key input detectingoperation of the embodiment shown in FIG. 1;

FIG. 3 is a flowchart showing the operation of a power source linecontrol circuit in the embodiment of FIG. 1;

FIG. 4 is a block diagram showing another embodiment of the presentinvention;

FIG. 5 is a flowchart showing the operation of a power source line/mutecontrol circuit in the embodiment of FIG. 4;

FIG. 6 is a block diagram showing a further embodiment of the presentinvention; and

FIG. 7 is a flowchart showing the operation of a power sourceline/volume control circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown an embodiment of the presentinvention in which a car telephone is embodied as a radio telephoneapparatus. The illustrated car telephone roughly comprises a transceiverunit 1 and a control unit 2. The transceiver unit 1 is installed, forexample, within a trunk of a car, while the control unit 2 is installed,for example, by a driver's seat. More specifically, the transceiver unit1 includes a power supply 11 for receiving power from a battery 3 togenerate power source voltages V_(CC1) and V_(CC2) necessary in thetransceiver 1 and the control unit 2, a controller 12 for controllingthe operation of the overall transceiver unit 1, a radio circuit 13 forestablishing a radio circuit with a base station (not shown), an audiocircuit 14 for processing an audio signal received from the radiocircuit 13 and an audio signal to be sent to the radio circuit 13, apower source line switch 15 provided between the battery 3 and the powersupply 11 for cutting off the supply of power to the power supply 11,and a power source line control circuit 16 for controlling the turningON and OFF operation of the power source line switch 15. The controller12 has a talk state detection part 17 for detecting whether or not thecar telephone is in a talk state.

The control unit 2, on the other hand, includes a key pad 21 throughwhich a dial number or the like is input, a controller 22 forcontrolling the operation of the entire control unit 2, a talk receiver25 for receiving a voice signal transmitted from the transceiver unit 1,a talk transmitter 24 for transmitting a voice signal to the transceiverunit 1, a loudspeaker 26 for generating a ringing tone, and a powersource key input detecting circuit 27 for detecting the operation of apower source key.

The control unit 2 is coupled to the party telephone set (an ordinaryhome telephone set or another car telephone) through an antenna 4, aspatial radio circuit and a base station to form a talk path with theparty telephone set, whereby a speech can be realized between thecontrol unit 2 and the party telephone set through the talk receiver 25and the talk transmitter 24.

The talk state detection part 17 in the controller 12 detects whether ornot the car telephone is in the talk mode by detecting a supervisoryaudio tone from the base station.

Specifically, once a speech communication link using speech radiochannels, which are changed over from control radio channels, areestablished between a car telephone and a base station, a supervisoryaudio tone signal is transmitted with speech signals from the basestation over the speech radio channels. The supervisory audio tonesignal has a predetermined frequency component and may be extracted fromreceived signals in the radio circuit 13 by a filtering technique. Whenthe supervisory audio tone is extracted, the radio circuit 13 applies adetection signal to the controller 12. Thus, the talk state detectionpart 17 in the controller may determine whether a speech communicationlink is established.

It should be noted that the talk state detection part 17 may detect thatthe car telephone is in the talk mode when the speech radio channels areestablished instead of detecting the supervisory audio signal.

One of keys in the key pad 21 is commonly used also as the power sourceswitch for turning ON and OFF the power supply of the car telephone, sothat, for example, when the user continuously depresses this key for apredetermined period of time, the power source key input detectingcircuit 27 detects the depressed state of the key and sends a powersource key operation signal to the power source line control circuit 16in the transceiver unit 1.

Shown in FIG. 2 is a flowchart for explaining an example of the powersource key detecting operation of the power source key input detectingcircuit 27. More in detail, when one of the keys (which will be referredto as the power source key, hereinafter) of the key pad 21 used as apower source key is turned ON (depressed) (step 101), a timer fordetecting the expiration of a predetermined time period is started up(step 102). Subsequently, the detection circuit 27 checks whether or notthe power source key is depressed (step 103) and whether or not thetimer expires (times up) (step 104). If the depression of the powersource key is continued until the timer expires, then the power sourcekey input detection circuit 27 sends a power source key operation signalto the power source line control circuit 16 within the transceiver 1(step 105).

The power source line control circuit 16 of the transceiver unit 1, whenreceiving the power source key operation signal from the power sourcekey input detection circuit 27, examines, on the basis of an outputreceived from the talk state detection part 17, whether or not the cartelephone is communicating with another party. When the power linecontrol circuit 16 determines that the car telephone is notcommunicating, i.e., detects a non-talk state of the talk statedetection part 17, the power control circuit 16 responds to the receivedpower source key operation signal and controls the turning ON/OFFoperation of the power source line switch 15. More specifically, if thepower source line switch 15 is in its OFF state, then the power linecontrol circuit 16 turns On the power source line switch 15 in responseto the power source key operation signal; while if the switch 15 is inits ON state, then the circuit 16 turns OFF the power source line switch15 in response to the power source key operation signal.

When the power source line control circuit 16 detects the car telephonein the communication mode on the basis of the output of the talk statedetection part 17, on the other hand, the circuit 16 will not respond tothe power source key operation signal even if the power source keyoperation signal is provided to the circuit 16, and thus will not turnOFF the power source line switch 15.

FIG. 3 shows a flowchart for explaining the operation of the powersource line control circuit 16. More in detail, the circuit 16, whenreceiving the power source key operation signal from the power sourcekey input detection circuit 27 (step 201), checks whether or not the cartelephone is in the communication mode (step 202). When the power sourceline control circuit 16 determines the system not in the communicationmode, then it examines whether or not the power source line switch 15 isin the ON state (step 203). If so, then the circuit 16 turns OFF thepower source line switch 15 (step 204), while if not then the circuit 16turns ON the switch 15 (step 204). When the car telephone is in thecommunication mode, however, the circuit 16 will not respond to thepower source key operation signal and terminate this flow.

Thus, even when the user erroneously touches the power source switch keyas one of the keys of the key pad 21 during the telephone communication,it can be avoided that the power supply of the car telephone is turnedOFF and the talk path is cut off.

Although explanation has been made as to the case where one of the keysin the key pad 21 is commonly used also as the power source switch inthe foregoing embodiment, the similar explanation may hold true for thecase where a dedicated power source switch is integrally provided withthe handset. Further, the transceiver unit 1 has been providedseparately from the control unit 2, but the units 1 and 2 may beintegrally combined to form a portable type with the small sized battery3.

With such an arrangement, even if the power source switch is erroneouslyoperated to instruct the turning OFF of the apparatus power supply, thisOFF instruction can be invalidated so long as the apparatus is in thecommunication mode, thus enabling the avoidance of unintentional cuttingoff of the talk path during the apparatus communication.

There is shown in FIG. 4 a block diagram of another embodiment of thepresent invention, in which the same parts as those in FIG. 1 aredenoted by the same reference numerals and explanation thereof isomitted. In the drawing, the transceiver unit 1 contains a mute switch19 which cuts off or deadens a voice sent from the transmitter 24 of thecontrol unit 2, while the control unit 2 contains a power source/mutekey input detection circuit 28. The transceiver unit 1 further containsa power source line/mute control circuit 18 which turn ON or OFF thepower source line switch 15 and the transmission talk muting switch 19on the basis of output signals received from the two detection circuits,i.e., the talk state detection part 17 for detecting whether or not theapparatus is in the talk mode and the power source/mute key inputdetection circuit 28.

In the present embodiment, two functions of an ON/OFF function of theapparatus power supply and a mute function of deadening a transmissionvoice are allocated to one of the keys in the key pad 21, so that thepower source/mute key input detection circuit 28, when detecting theoperation (continuous depression for a time period exceeding thepredetermined time) of the key having the aforementioned two functions,sends a power source/mute key operation signal to the power sourceline/mute control circuit 18 of the transceiver unit 1.

With such an arrangement as mentioned above, the power source line/mutecontrol circuit 18 operates as shown by a flowchart in FIG. 5. That is,when the circuit 18 receives the power source/mute key operation signalfrom the circuit 28 (step 301) and the talk state detection part 17detects that the car telephone is in the non-talk state, the circuit 18recognizes the aforementioned key of the key pad 21 as the ON/OFFfunction key of the telephone power supply and controls the ON and OFFoperation of the power source line switch 15. More specifically, whenthe power source line switch 15 is in the ON state (step 303), the powersource line/mute control circuit 18 responds to the power source/mutekey operation signal received from the power source/mute key inputdetection circuit 28 and turns OFF the power source line switch 15 (step304). When the power source line switch 15 is in the OFF state (step303), the power source line/mute control circuit 18 responds to thepower source/mute key operation signal received from the powersource/mute key input detection circuit 28 and turns ON the power sourceline switch 15 (step 305).

When the talk state detection part 17 detects that the car telephone isin the talk mode, however, the power source line/mute control circuit 18recognizes the aforementioned key of the key pad 21 as a talk voicemuting key and controls the ON and OFF operation of the muting switch19. More in detail, if the muting switch 19 is in the ON state (step306), then the power source line/mute control circuit 18, responsive tothe power source/mute key operation signal received from the powersource/mute key input detection circuit 28, turns OFF the muting switch19 (step 307); while if the muting switch 15 is in the OFF state (step303), then the power source line/mute control circuit 18, responsive tothe power source/mute key operation signal received from the powersource/mute key input detection circuit 28, turns OFF the muting switch19 (step 308).

That is, the function of turning ON and OFF the telephone power supplyis unnecessary in the talk mode, while the mute function is unnecessaryin the non-talk mode. Accordingly, when the two functions of the ON/OFFfunction of the telephone power supply and the mute function ofdeadening a transmission voice are allocated to one key as stated aboveand are selectively used depending on the talk or non-talk mode, the cartelephone can realize the saving of the number of necessary functionkeys and also can satisfy a demand of increasing the number of necessaryfunction keys. In addition, the ON/OFF function of the power supplybecomes valid only when the car telephone is in the talk mode, so thateven when the user erroneously touches the above function key in thetalk mode, it can be avoided that the telephone power supply isunintentionally turned OFF and thus the talk path is cut off.

With the present arrangement, the ON/OFF function of the telephone powersupply and the mute function of attenuating a transmission talk voiceare allocated to one of the keys in the dial key pad, and there isprovided a detecting means for detectin whether or not the car telephoneis in the talk mode through the spatial radio circuit, so that mutecontrol is carried out on the basis of the ON or OFF output of said keyin the talk mode, while ON/OFF control of the telephone power supply iscarried out in the non-talk mode. As a result, the car telephone canrealize the saving of the number of necessary function keys and cansatisfy a demand of increasing the number of necessary functions whilenot involving the increse of the number of keys in the key pad and theenlargement of the size of the key pad. In addition, since the ON/OFFfunction of the power supply becomes valid only in the non-talk mode,even erroneous depression of the above function key will cause theprevention of unintentional turning OFF of the telephone power supplyand thus the cutting off of the talk path.

FIG. 6 shows a block diagram of a further embodiment of the presentinvention, in which embodiment the transceiver unit 1 contains a volumecircuit 190 which controls the volume of a voice to be sent to thereceiver 25 of the control unit 2 and the control unit 2 contains apower source/volume key input detection circuit 29. The transceiver unit1 further contains a power source line/volume control circuit 180 whichcontrols the ON and OFF operation of the power source line switch 15 andthe volume circuit 190 on the basis of output signals received from thetwo detection circuits, i.e., the talk state detection part 17 fordetecting whether or not the car telephone is in the talk state and thepower source/volume key input detection circuit 29.

In the illustrated embodiment, the ON/OFF function of the telephonepower supply and a volume function of controlling the volume of areceived talk voice are allocated to one of keys in the key pad 21. Whenthe power source/volume key input detection circuit 29 detects adepressed state of the above key to which the above two functions areallocated (continuous depression of the key for a time period exceedinga predetermined time), the circuit 29 sends a power source/volume keyoperation signal to the power source line/volume control circuit 180 inthe transceiver unit 1.

In such an arrangement as mentioned above, the power source line/volumecontrol circuit 180 operates as shown by a flowchart in FIG. 7. Morespecifically, when the power source line/volume control circuit 180receives the power source/volume key operation signal (step 401) anddetects that the system is already in the non-talk mode on the basis ofan output signal from the talk state detection part 17 (step 402), thecircuit 180 recognizes the above key of the key pad 21 as the ON/OFFfunction key of the telephone power supply and controls the ON and OFFoperation of the power source line switch 15. More in detail, if thepower source line switch 15 is in its ON state (step 403), the thecircuit 180 turns OFF the power source line switch 15 (step 404), while,if the power source line switch 15 is in its OFF state, then the circuit180 turns ON the power source line switch 15 (step 405).

When the talk state detection part 17 detects that the car telephone isin the talk mode, however, the circuit 180 recognizes the above key ofthe key pad 21 as the volume key for controlling the volume of areceived talk voice and controls the volume circuit 190. For example,responsive to the power source/volume key operation signal received fromthe power source/volume key input detection circuit 29, the power sourceline/volume control circuit 180 increases or decreases the volume of areceived talk voice, which is repeated.

Even with such an arrangement as mentioned above, the radio apparatuscan realize the saving of the number of necessary function keys and canmeet a demand of increasing the number of necessary functions in theapparatus while not involving the increase of the number of necessarykeys in the key pad and also while not involving the enlargement of thesize of the key pad. Since the ON/OFF function of the power supplybecomes valid only in the non-talk mode, even when the user erroneouslytouches the above function key during the apparatus conversationoperation, it can be avoided that the apparatus power supply isunintentionally turned OFF and the talk path is cut off.

The function key commonly used also as the power source key is notlimited to the mute and volume keys and other suitable function keys maybe used instead only in the talk mode.

In the above described embodiments, although arrangements of a cartelephone and its operation were explained in detail, it is apparent tothose skilled in the art to apply the present invention to a cordlesstelephone, cellular portable telephone and so on. Still, the presentinvention may be applied to any radio telecommunication apparatus with apower ON/OFF switch.

What is claimed is:
 1. A radio telephone apparatus comprising:atransceiver unit having a power supply and a radio circuit; a controlunit having a receiver and a keypad; a power source key, included insaid keypad, for turning ON and OFF said power supply, wherein saidpower supply is turned ON solely in response to an actuation of saidpower source key; talk state detection means, included in thetransceiver unit, for detecting whether or not said apparatus is in atalk mode on the basis of the establishment of a speech radio channel bysaid radio circuit; and control means, included in the transceiver unit,for preventing said power supply from being turned OFF in response to aswitching operation of said power source key when said talk statedetection means detects that the apparatus is in said talk mode.
 2. Aradio telephone apparatus as set forth in claim 1, wherein said controlmeans includes a power source line switch provided in a power supplyline leading to said power supply and inhibit means for inhibiting OFFoperation of said power source line switch when said talk statedetection means detects that said apparatus is in the talk mode.
 3. Amethod of controlling a radio telephone apparatus having a transceiverunit including a power supply and a radio circuit, said methodcomprising the steps of:turning ON said apparatus by operating an ON/OFFkey, wherein said apparatus is turned ON solely in response to anactuation of said ON/OFF key; detecting whether or not said apparatus isin a talk mode on the basis of the detection of a supervisory audio tonesignal transmitted by a base station; and inhibiting user-activated OFFoperation of said power supply when the apparatus is in the talk mode.4. A method as set forth in claim 3, wherein said inhibiting step iscarried out by inhibiting OFF operation of a power source line switchdisposed in a power supply line leading to said power supply.
 5. Amethod as set forth in claim 3, further comprising a step of detectingwhether or not a switching operation has been provided to turn OFF saidpower supply, and wherein said inhibit step is carried out by inhibitingOFF operation of said power supply so long as said apparatus is in thetalk mode even when a switching operation has been provided to turn OFFthe power supply.
 6. A radio telephone apparatus comprising:atransceiver unit having a power supply and a radio circuit; a controlunit having a receiver and a keypad; a power source key, included insaid keypad, for turning ON and OFF said power supply, wherein saidpower supply is turned ON solely in response to an actuation of saidpower source key; talk state detection means, included in thetransceiver unit, for detecting whether or not said apparatus is in atalk mode on the basis of the establishment of a speech radio channel bysaid radio circuit; a key operation state detection circuit, included inthe control unit, for detecting whether or not said power source key hasbeen operated; and control means, included in the transceiver unit, forcontrollably turning OFF said power supply when said talk statedetection means fails to detect that said apparatus is in the talk modeand when said key operation state detection circuit detects that thepower source key has been operated, and for controllably inhibiting OFFoperation of the power supply when both said talk state detection meansdetects that said apparatus is in the talk mode and said key operationstate detection circuit detects that the power source key has beenoperated.
 7. A radio telephone apparatus as set forth in claim 6,wherein said control means includes a power source line switch providedin a power supply line leading to said power supply and inhibit meansfor inhibiting OFF operation of said power source line switch when saidtalk state detection means detects that said apparatus is in the talkmode.
 8. A radio telephone apparatus as set forth in claim 6, whereinsaid control means executes a muting operation when said talk statedetection means detects that said apparatus is in the talk mode and whensaid key operation state detection circuit detects that said powersource key has been operated.
 9. A radio telephone apparatus as setforth in claim 6, wherein said control means executes a volume adjustingoperation when said talk state detection means detects that saidapparatus is in the talk mode and when said key operation statedetection circuit detects that said power source key has been operated.10. A method of controlling a radio telephone apparatus having atransceiver unit including a power supply and a radio circuit, saidmethod comprising the steps of:turning ON said apparatus by operating anON/OFF key, wherein said apparatus is turned ON solely in response to anactuation of said ON/OFF key; detecting whether or not said apparatus isin a talk mode on the basis of the detection of a supervisory audio tonesignal transmitted by a base station; detecting whether or not aswitching operation has been performed to turn OFF said power supply;and inhibiting OFF operation of the power supply when the apparatus isin said talk mode even when a switching operation is performed to turnOFF the power supply.
 11. A method as set forth in claim 10, whereinsaid inhibiting OFF operation step is carried out by inhibiting OFFoperation of a power source line switch disposed in a power supply lineleading to said power supply.
 12. A method as set forth in claim 10,further comprising the step of performing a muting operation when it isdetected that said apparatus is in the talk mode and a switchingoperation to turn OFF said power supply has been performed.
 13. A methodas set forth in claim 10, further comprising the step of performing avolume adjusting operation when it is detected that said apparatus is inthe talk mode and a switching operation to turn OFF said power supplyhas been performed.
 14. A radio telephone apparatus having a radiocircuit, comprising:a power supply; a power source line switch forsupplying a voltage from a power source to said power supply; a powersource switch for turning OFF said power supply and for turning ON saidpower supply solely in response to an actuation of said power sourceswitch; first detection means for detecting an ON or OFF state of saidpower source switch; second detection means for detecting whether or notsaid apparatus is in a talk mode on the basis of the establishment of aspeech radio channel by said radio circuit; and control means forinhibiting switching of said power source line switch to its OFF stateby means of said power source switch in said talk mode and for allowingswitching of the power source line switch to the OFF state only in anon-talk mode on the basis of detection signals received from said firstand second detection means.
 15. A radio telephone apparatus,comprising:a power supply; a transceiver unit for establishing a talkpath through a radio link between said transceiver unit and a basestation; a control unit connected to said transceiver unit through awire line and having a receiver, a transmitter and a keypad, wherein anON/OFF function of said power supply and a muting function which mutes atransmitted voice, are allocated to one key in said keypad which turnsON said power supply, and wherein said power supply is turned ON solelyin response to an actuation of said one key; first detection means fordetecting an ON or OFF state of said one key; second detection means fordetecting whether said apparatus is in a talk mode or a non-talk modethrough said radio link on the basis of the establishment of a speechradio channel by said radio circuit; and control means for performingsaid muting function when an ON or OFF output of said one key isdetected by said first detecting means and said apparatus is in saidtalk mode, and for performing said ON/OFF function of said power supplywhen said apparatus is in a non-talk mode.
 16. A radio telephoneapparatus, comprising:power supply means for supplying the apparatuswith electric power; an operator-actuatable switch; detection means fordetecting an actuation of said operator-actuatable switch and forgenerating a detection signal in response to the detection of theactuation, wherein said power supply means is turned ON solely inresponse to the actuation of said operator-actuatable switch;establishing means for establishing a speech communication link withanother apparatus over one or more radio channels; and power supplycontrol means, responsive to the detection signal, for controlling thepower supply means so that power supplied to the apparatus is initiatedor terminated in response to the detection signal when the speechcommunication link is not established by said establishing means and sothat power supplied to the apparatus is not terminated in response tosaid detection signal when the speech communication link is establishedby said establishing means.
 17. The apparatus of claim 16, furthercomprising control means for performing a function other than supplyingpower in response to said detection signal while the speechcommunication link is established by said establishing means.
 18. Theapparatus of claim 17, further comprising:audio input means forprocessing input audio signals; and broadcasting means for broadcastingsignals applied thereto through the speech communication link, whereinsaid control means prevents said audio input means from processing saidinput audio signals in response to said detection signal while thespeech communication link is established by said establishing means. 19.The apparatus of claim 17, further comprising:audio input means forprocessing input audio signals; and broadcasting means for broadcastingsignals applied thereto through the speech communication link, whereinsaid control means controls the magnitude of signals to be transmittedfrom said audio input means to said broadcasting means in response tosaid detection signal while the speech communication link is establishedby said establishing means.
 20. The apparatus of claim 16 wherein saidoperator-actuatable switch comprises a depressible key switch and meansfor detecting the actuation of said operator-actuatable switch when thedepressible key switch is continuously depressed for a predeterminedtime period.
 21. A radio telephone apparatus, comprising:power supplymeans for supplying the apparatus with electric power; anoperator-actuatable switch; wherein said power supply means is turned ONsolely in response to the actuation of said operator-actuatable switchestablishing means for establishing a speech communication link withanother party; power supply control means for controlling the powersupply means so that power supplied to the apparatus is initiated orterminated in response to the actuation of said operator-actuatableswitch when the speech communication link is not established by saidestablishing means, and so that the power supplied to the apparatus isnot terminated in response to the actuation of said operator-actuatableswitch while the speech communication link is established by saidestablishing means.
 22. The apparatus of claim 21, furthercomprising:audio input means for processing input audio signals;broadcasting means for broadcasting signals applied thereto through thespeech communication link; and control means for preventing said audioinput means from processing the input audio signals in response to anactuation of said operator-actuatable switch while the speechcommunication link is established by said establishing means.
 23. Theapparatus of claim 21, further comprising:audio input means forprocessing input radio signals; broadcasting means for broadcastingsignals applied thereto through the speech communication link; andcontrol means for controlling the magnitude of signals to be transmittedfrom said audio input means to said broadcasting means in response tothe actuation of said operator-actuatable switch while the speechcommunication link is established by said establishing means.
 24. Aradio telephone apparatus, comprising:an operator-actuatable switch;power supply means for supplying the apparatus with electric power inresponse to an actuation of said operator-actuatable switch, wherein thepower supplied to the apparatus is initiated solely in response to anactuation of said operator-actuatable switch; determining means fordetermining if a speech communication link is established between theradio telephone apparatus and another apparatus; audio input means forprocessing input audio signals; broadcasting means for broadcastingsignals applied thereto through the speech communication link; andcontrol means, responsive to an actuation of said operator-actuatableswitch, for continuing the power supply to the apparatus and controllingthe magnitude of signals to be transmitted between said audio inputmeans and said broadcasting means if the speech communication link isestablished.
 25. The apparatus of claim 24, wherein said control meansdisconnects said audio input means from said broadcasting means inresponse to the actuation of said operator-actuatable switch if thespeech communication link is established, whereby saidoperator-actuatable switch is used as a mute switch while the speechcommunication link is established.
 26. The apparatus of claim 24,wherein said control means increases or decreases a volume level ofsignals to be transmitted from said audio input means to saidbroadcasting means in response to the actuation of saidoperator-actuatable switch if the speech communication link isestablished, whereby said operatoractuatable switch is used as a volumeswitch while the speech communication link is established.
 27. Theapparatus of claim 24, wherein said determining means determines that aspeech communication link is established between the radio telephoneapparatus and another apparatus when a tone signal of a predeterminedfrequency is received through the speech communication link.
 28. A radiotelephone apparatus, comprising:an operator-actuatable switch; powersupply means for supplying the apparatus with electric power responsiveto an actuation of said operator-actuatable switch, wherein the powersupplied to the apparatus is initiated solely in response to anactuation of said operator-actuatable switch; determining means fordetermining if a speech communication link is established between theradio telephone apparatus and another apparatus; and control means,responsive to an actuation of said operator-actuatable switch, forcontinuing the power supply of the apparatus and performing a functionother than supplying the apparatus with electric power if the speechcommunication link is established.
 29. The apparatus of claim 28,further comprising:audio input means for processing input audio signals;and broadcasting means for broadcasting signals applied thereto throughthe speech communication link, wherein said control means disconnectssaid audio input means from said broadcasting means in response to theactuation of said operator-actuatable switch if the speech communicationlink is established, whereby said operator-actuatable switch is used asa mute switch while the speech communication link is established. 30.The apparatus of claim 28, further comprising:audio input means forprocessing input audio signals; and broadcasting means for broadcastingsignals applied thereto through the speech communication link, whereinsaid control means increases or decreases a volume level of signals tobe transmitted from said audio input means to said broadcasting means inresponse to the actuation of said operator-actuatable switch if thespeech communication link is established, whereby saidoperator-actuatable switch is used as a volume switch while the speechcommunication link is established.
 31. The apparatus of claim 28,wherein said determining means determines that a speech communicationlink is established between the radio telephone apparatus and anotherapparatus when a tone signal of a predetermined frequency is receivedthrough the speech communication link.
 32. A method of using anoperator-actuatable switch provided in a radio telephone apparatus bothas a power switch and a volume control switch, comprising the stepsof:(a) supplying the apparatus with electric power in response to anactuation of said operator-actuatable switch, wherein the power suppliedto the apparatus is initiated solely in response to an actuation of saidoperator-actuatable switch; (b) determining if a speech communicationlink is established between the radio telephone apparatus and anotherapparatus; and (c) continuing the power supply to the apparatus andcontrolling the magnitude of signals to be transmitted between an audioinput means and a broadcasting means in response to an actuation of saidoperator-actuatable switch if the speech communication link isestablished.
 33. The method of claim 32, wherein the continuing stepcomprises a step of disconnecting said audio input means from saidbroadcasting means in response to the actuation of saidoperator-actuatable switch if the speech communication link isestablished, whereby said operator-actuatable switch is used as a muteswitch while the speech communication link is established.
 34. Themethod of claim 32, wherein the continuing step comprises a step ofincreasing or decreasing a volume level of signals to be transmittedfrom said audio input means to said broadcasting means in response tothe actuation of said operator-actuatable switch if the speechcommunication link is established, whereby said operator-actuatableswitch is used as a volume switch while the speech communication link isestablished.
 35. The method of claim 32, wherein the determining stepcomprises a step of detecting a tone signal of a predetermined frequencyin signals received through the speech communication link.
 36. A methodof using an operator-actuatable switch provided in a radio telephoneapparatus both as a power switch and another function switch, comprisingthe steps of:(a) supplying the apparatus with electric power responsiveto an actuation of said operator-actuatable switch, wherein the powersupplied to the apparatus is initiated solely in response to anactuation of said operator-actuatable switch; (b) determining if aspeech communication link is established between the radio telephoneapparatus and another apparatus; and (c) continuing the power supply tothe apparatus and performing a function other than supplying theapparatus with electric power in response to an actuation of saidoperator-actuatable switch if the speech communication link isestablished.
 37. The method of claim 36, wherein the continuing stepcomprises a step of disconnecting an audio input means from abroadcasting means in response to the actuation of saidoperator-actuatable switch if the speech communication link isestablished, whereby said operator-actuatable switch is used as a muteswitch while the speech communication link is established.
 38. Themethod of claim 36, wherein the continuing step comprises a step ofincreasing or decreasing a volume level of signals to be transmittedfrom an audio input means to a broadcasting means in response to theactuation of said operator-actuatable switch if the speech communicationlink is established, whereby said operator-actuatable switch is used asa volume switch while the speech communication link is established. 39.The method of claim 36, wherein the determining step comprises a step ofdetecting a tone signal of a predetermined frequency out of signalsreceived through the speech communications link.
 40. A method ofcontrolling a radio telephone apparatus having a transceiver unitincluding a power supply and a ratio circuit, said method comprising thesteps of:turning ON said apparatus by operating an ON/OFF key, whereinsaid apparatus is turned ON solely in response to an actuation of saidON/OFF key; detecting whether or not the apparatus is in a talk mode onthe basis of the establishment of a speech radio channel by said radiocircuit; inhibiting an OFF operation of said power supply when theapparatus is in the talk mode; and detecting whether or not a switchingoperation has been performed to turn OFF said power supply, wherein saidinhibiting step is carried out by inhibiting the OFF operation of saidpower supply so long as the apparatus is in the talk mode even when aswitching operation has been performed to turn OFF the power supply. 41.A method as set forth in claim 40, wherein said talk mode detecting stepis carried out by detecting whether or not the apparatus is in the talkmode on the basis of an output of said radio circuit.
 42. A method asset forth in claim 40, wherein said talk mode detecting step is carriedout by detecting whether or not the apparatus is in the talk mode on thebasis of a stage in a control step of said transceiver unit.
 43. Amethod as set forth in claim 40, wherein said inhibiting step is carriedout by inhibiting the OFF operation of a power source link switchdisposed in a power supply line leading to said power supply.